Especially out there you would surely do best to grow your tomatoes inside a plastic shelter. This can be quite important in the earlier, cooler parts of the season as well as after the peak of warm temperatures - I've had them blight off as early as August on Camano Island, just as they were coming into production.

I've found that Baker Creek Seeds has one of the best selections of heirloom tomatoes. (Or any heirlooms for that matter) They're out of Missouri so you have to be careful and choose only the earliest ripening ones. They'll send you a catalog free...it's fun to look at even if you don't buy anything.

You might also check out Territorial Seed Company. They're here in Oregon and carry a lot of locally adapted varieties. Kinda spendy though.